About Voxel Skinning

Voxel is a term used in 3D to describe the amount of capacity or space a 3D object occupies. Voxels are useful for representing regularly-sampled spaces that are dissimilarly filled.

Voxelization is the act of converting a 3D geometric object into a set of voxels that closely approximates the input mesh. This process is similar to the rasterization process in 2D.

In 3ds Max you can apply the voxelization any time after you have applied skin, and to a selected part of the mesh.

The process essentially converts a mesh (or meshes) into voxels based on a given resolution. It then does a geodesic measurement within this voxel structure to find the nearest joint to any given vertex. This is much more reliable and predictable than the traditional method, which just does a simple linear distance measurement.

The Voxel binding method lets you select multiple meshes, treating all shapes as a single volume and giving continuous weighting across the geometry. This method voxelizes the input geometry to calculate binding weights derived from the geodesic distance between voxels on the skeleton and the mesh. Voxel binding is designed to work with meshes that may contain non-manifold, non-watertight, intersecting triangles or are comprised of multiple connected components. To be used effectively, two requirements need to be respected:

All joint influences must be enclosed inside the mesh volume to correctly compute geodesic distance.
Normals for geometry front faces should be oriented to point outwards.

Tip: There may be problems with voxelization for the neck, head and fingers, as these vertices are too close for voxels to work normally. For the neck, the pivot is too close to the jaw, so weights spill over to the chin. The head bone pivot should be more towards the back and you should use several, smaller neck bones to reduce this effect. For the head you can also select the head/neck and shoulder vertices and run voxel weighting with the falloff turned up. This will reduce the weight smoothness so the neck will have less influence on the chin. For the fingers, you can either select the hand and run it at 512 (as the selection is much smaller than the whole mesh, you will get better detail) or you can use the heat map.

Note: There may be discontinuities along open edges.